Matt and I have been looking in more detail at indications of maturity in sauropod skeletons, as we prepare the submission of the paper arising from our response to Woodruff and Fowler (2012) [part 1, part 2, part 3, part 4, part 5, part 6].  Here is an oddity. Sacra of Haplocanthosaurus . Top, H . utterbacki holotype CM 879 in right lateral view, from Hatcher (1903:fig.